1. Field of Invention
The present invention relates to a power system with temperature compensation control.
2. Description of Related Art
Referring to FIG. 1, an electronic device often requires two power supply paths. When it is operated under an external power source, the external power source supplies power to a load 2 and charges a battery BATT; when the external power source does not exist, the battery BATT supplies power to the load 2. In the prior art shown in the drawing, the external power supply path is controlled by a linear voltage converter circuit 10. This linear voltage converter circuit 10 for example is a simple switch or an LDO (Low Drop-Out) circuit, including a power transistor switch P0 controlled by an LDO control circuit or a switch control circuit 11. The path through which the external power source charges the battery BATT and the battery BATT supplies power to the load 2 is controlled by a power transistor switch P1, wherein the switch P1 is controlled by a constant current or constant voltage (CC/CV) dynamic control circuit 20. The switch P1 is CC/CV dynamically controlled when the battery BATT is being charged, but operates as a simple switch when the battery BATT supplies power to the load 2.
In the foregoing prior art, the LDO 10 and the CC/CV dynamic control circuit 20 are well-know to a person skilled in this art, and their details are thus omitted here.
The foregoing prior art in FIG. 1 has the following drawback. Because the circuit uses the linear voltage converter circuit, the voltage difference between the external power source and the battery causes a heat dissipation issue. This issue occurs in either the power switch P0 or the power switch P1. Thus, it is desired to provide a solution to it.